Use VLC as Video Convertor !
1. Click Media --> Convert/Save.
2. Select the file you want to convert using Add button. Now click on Convert/Save button and next window will appear.
3. Now click on browse and select where you want to save the converted file. Down under you can see a drop down menu from which you can select the output format.
4. Hit the Start button, sit back and relax. 😀